Dishwasher drain airgap



A. M. BARON DISHWASHER DRAIN AIRGAP Filed Aug. 13, 1962 Nov. 3, 1964 ..2A. V5 x United States Patent O 3,155,106 DISHWASHER DRAIN ARG-AP AlfredM. Baron, Los Angeies, Calif., assigner to United States BrassCorporation, a corporation of Minnesota Filed Aug. 13, 1962, Ser. No.216,545 2 Claims. (Cl. 137-216) This invention relates to dishwasherdrain plumbing and, more particularly, to improvements therein.

The modern dishwasher usually discharges the water used for washingdishes into the sewer line by pumping this water from the bottom of thedishwasher up until it is high enough to be able to How into the drainpipe of an adjacent sink. Should the pump motor fail for any reason,then a condition can arise wherein the drain pipe of the dishwasher caneffectively form a siphon, as a result of which the waste water of thesink can be siphoned back into the dishwasher. This constitutes a healthhazard. To avoid this, there is a requirement that at some point withinthe drain `or discharge connection between the dishwasher and the sinkwaste pipe, air be permitted to enter in order to prevent any Siphonaction from occurring. A number of different plumbing fixtures have beendevised for performing what is called an isolation between thedishwasher drain and the main drain line. While these are effective forperforming the required isolation, they have not been satisfactorybecause of the diculty in their installation, as Well as theirmaintenance. The problem of maintenance arises if the person using thedishwasher is not careful in removing food particles from the dishesand/or utensils before inserting these into the dishwasher. These foodparticles can collect at any restriction or large bend in the dischargepipe. Since both of these are usually present in the region of thedischarge pipe, where the drain air gap occurs, the pipe can becomeplugged at this region. With the presently known arrangement, theopening and cleaning of the pipe is extremelydiicult and time-consuming.

An object of this invention is the provision of draingap plumbing whichmay be more quickly and easily installed than has been possibleheretofore.

Another object of the present invention is the provision of drain-gapplumbing which is simpler to maintain when necessary than has beenpossible heretofore:

Yet another object of the present invention is the provision of noveland useful drain-gap plumbing which is easier to manufacture vthanpreviously known devices.

These and other objects of the invention may be achieved in anarrangement wherein the drain pipe from a dishwasher is terminatedadjacent a structure which serves the function of redirecting the flowof the water from the pipe which strikes the structure into a path whichis opposite in direction to the direction of the water in the pipe andwhich is adjacent the pipe. This how-redirecting structure extendsadjacent the pipe for a suiiicient distance to insure that theredirected water flow will continue to flow in the reverse direction.There is a space between the termination of this redirecting structureand the beginning of the pipe which carries away The waste water. Atthis point, air is introduced in order to prevent any siphoning actionfrom occurring. Installation of the drain-gap plumbing is simplyeffectuated by passing the pipe which carries the dishwasher waste waterback to the sink drain through an opening normally provided for it inthe sink. This pipe is threaded. On the portion of this pipe whichextends through the opening in the sink, there is screwed a cap havinginternal threads, which cap includes the dow-reversing member. The capis threaded down on the pipe until it is on the surface of the sink. Theassembly is completed by a nut previously threaded on the portion of thepipe which is on the other Vside of the sink structure, which is broughtup tight to hold the assembly in place.

The novel features that are considered characteristic of this inventionare set forth with particularity in the appended claims. The inventionitself, both as to its organization and method of operation, as well asadditional objects and advantages thereof, will best be understood fromthe following description when read in connection with the accompanyingdrawings, in which:

FIGURE l is a drawing of a dishwasher and sink, exemplifying thelocation of the embodiment of the invention;

FIGURE 2 is a cross-sectional View of an embodiment of the invention;and

FIGURE 3 is a view in section along the line 3 3 of FIGURE 2. Y

Reference is now made to FIGURE l. This shows an arrangement ofdishwasher and sink with the embocliment ofthe invention placedto enablethe dishwasher to drain to the sink waste line. The dishwasher 10usually has a pump 12 -at the bottom. The dishwasher drain line 14 isbrought up to an elevation higher than the waste pipe 16 of the sinks18, 20. The structure 22 shown below the sink 18 represents a garbagedisposal device of the type which grinds foods tine enough to bedischarged down the drain pipe 16. A discharge pipe 24 connects thedrain-gap structure 26 to the garbage disposer 22. Provision is normallymade in these garbage disposer devices 22 for connection with the drainpipeV from a dishwasher.

The arrangement of the apparatus shown in FIGURE l is one for enablingthe pump 12 to pump the waste water from the dishwasherli into the-drainpipe 16. A drain gap 26, which is an serves the function of reversingthe ow of the water and also for providing yan air gap to prevent anySiphon action from occurring. It will be noted that the device 26 isattached to the surface of the sink.

FIGURE 2 is a cross section of the embodiment of the invention 26,whichV is shown in FIGURE 1. FIGURE 3 is a cross-sectional view alongthe lines 3-3 of FIG- URE 2. The invention includes a pipe section 39,which may be called the inflow pipe. This inflow pipe is connected `tothe pipe 14 and terminates above the drainboard 32 of the sink. Oppositethe open end of the pipe 30 is a cap member 34, which serves thefunction of reversing or redirecting the ow of the water which s pumpedthrough the pipe 30. This member 34 effectively constltutes a cap whichis supported so that the pipe 30 1s within the opening of the cap. Thecap member walls entend down along the outside of the walls of theinflow plpe for a sufficient distance to insure that any water whosedirection of dow is redirected by striking the ciosed end of the capmember 34 will be guided into an outflow pipe 42.

The member 34, which can be termed an inner cap, is supported withinanother cap structure 38. The structure 38 may be termed an outer cap.The inner cap 34 1s spot-welded, or brazed, at the location 36 to theouter cap 38. The outflow pipe 42 has three sections which are brazed orsoldered together. These consist of a threaded section 42A, which iscoaxially positioned relative to the inliow pipe and overlaps the endsof the inner cap for a sutiicient distance to insure that the redirectedwater flow will enter and flow out of the outflow pipe without anybackup or splashing. The threaded section is connected to a right-anglepipe section 42B, which supports the inflow pipe. The right-angle pipesection is embodiment of this invention,

then connected to an external coupling section 42C, which couples to thepipe 24, leading to the garbage disposer 22.

An opening 40 exists at one side of the outer-cap member 38. Thus, aircan enter into the space between the top of the inner-cap member 34 andthe outer-cap member 38, and can ow along the sides of the inner-capmember and into the outflow pipe to admit atmospheric pressure to thespace between the termination of the inner-cap member and thecommencement of the outflow pipe 42. A ring 46, having internal threads,is brazed to the end of the outer cap member 38. The threads on the ringcan engage the threads on the section 42A for attaching the cap to theoutliow pipe and positioning the inner cap opposite the end of theinflow pipe 39.

Prior to mounting on the sink drainboard, the inner cap 34 and outer cap38 consist of one portion of the assembly. The inflow pipe 30, threadedpipe section 42A, and right-angle pipe 42B exists as a second assembledportion. To assemble these together on the sink drainboard is a simplematter. The inflow pipe 42 is inserted in the aperture provided thereforin the sink drainboard to a desired height, which can be fixed by a nut50, which is threaded on the threaded pipe section 42A. A washer 52 isinterposed between the nut and sink drainboard. The outer cap 38 is thenscrewed down on the outflow pipe until a junction is made with the topof the sini; drainboard. Connection can thereafter be made to the pipe14 and to the pipe 24.

In order to remove the assembly for cleaning, it is a simple matter toloosen up the nut 50 thereafter to unscrew the outer-cap member 38,whereupon access is had to the pipe sections for cleaning. Air canfreely enter the opening 40 and have access to the regions where reverseiiow of water 4occurs where the end of the inflow pipe opposes the innercap and is redirected down through the outow pipe.

There has accordingly been described and shown herein a novel, useful,and simple arrangement for providing an air gap in the pipe couplingbetween the drain of a dishwasher and the main drain of a sink. Assemblyof the arrangement is made very simply, and it also provides a simpleand convenient assembly for servicing and maintaining these pipes whenrequired. This apparatus also prevents any possibility of pump-backspillage due to possible pumping action of a garbage disposal when thereis a slight or marked clogging in the wasteline to which it is attached.It also eliminates cross-connections,

I claim:

1. Apparatus for providing a drain gap comprising an outer cap having acylindrical cavity which is open at one end, an inner cap smaller thansaid outer cap, means supporting said inner cap within the cavity ofsaid outer cap, said inner cap having a cylindrical cavity therein whichis open at one end, the openings of the cavities of both of said capsfacing in the same direction, an outilow pipe having one end extendinginto the outer cap cylindrical cavity and coupled to the walls thereof,an inflow pipe having a diameter which is less than that of said innercap, means supporting said inflow pipe coaxially within said outflowpipe and with one end extending Within the cavity of said inner capadjacent to the closed end of said inner cap cavity, and an opening inthe walls of said outer cap for admitting atmospheric pressure into thespace between said inner cap and said outliow pipe, said outflow pipehaving threads formed in its outer surface, means mounted on the Wallsof the cavity of said outer cap for threadably engaging said outer capwith the threads on said outflow pipes outer surface, and a nut threadedon said outflow pipes outer walls for enabling said apparatus to beclamped to a supporting surface between said nut and the end of saidouter cap.

2. Apparatus for providing a drain gap comprising an outflow pipe, aniniiow pipe of smaller diameter than said outow pipe, one of said inflowpipe and said outflow pipe being bent at an intermediate region, saidinflow pipe passing through the Wall of said outiiow pipe in sealingrelationship, one end portion of said inow pipe being substantiallycoextensive with one end portion of said outflow pipe and supportedcoaxially within said outflow pipe, an outer cap removably coupled tothe outiow pipe for closing said one end portion, an inner cap ofsmaller diameter than said outer cap carried by said outer cap, saidinner cap being of smaller diameter than said outow pipe and of largerdiameter than said inflow pipe, said inner cap being coaxial with saidinflow pipe and said outflow pipe with the wall of said inner capextending into the space between said inflow pipe and said outflow pipewhen said outer cap is coupled to said outow pipe, and an apertureformed in said outer cap at a level above the open end of said inner capfor contionuously admitting atmospheric pressure to the space betweensaid inner cap and said outow pipe.

References Cited in the lile of this patent UNITED STATES PATENTS

1. APPARATUS FOR PROVIDING A DRAIN GAP COMPRISING AN OUTER CAP HAVING ACYLINDRICAL CAVITY WHICH IS OPEN AT ONE END, AN INNER CAP SMALLER THANSAID OUTER CAP, MEANS SUPPORTING SAID INNER CAP WITHIN THE CAVITY OFSAID OUTER CAP, SAID INNER CAP HAVING A CYLINDRICAL CAVITY THEREIN WHICHIS OPEN AT ONE END, THE OPENINGS OF THE CAVITIES OF BOTH OF SAID CAPSFACING IN THE SAME DIRECTION, AN OUTFLOW PIPE HAVING ONE END EXTENDINGINTO THE OUTER CAP CYLINDRICAL CAVITY AND COUPLED TO THE WALLS THEREOF,AN INFLOW PIPE HAVING A DIAMETER WHICH IS LESS THAN THAT OF SAID INNERCAP, MEANS SUPPORTING SAID INFLOW PIPE COAXIALLY WITHIN SAID OUTFLOWPIPE AND WITH ONE END EXTENDING WITHIN THE CAVITY OF SAID INNER CAPADJACENT TO THE CLOSED END OF SAID INNER CAP CAVITY, AND AN OPENING INTHE WALLS OF SAID OUTER CAP FOR ADMITTING ATMOSPHERIC PRESSURE INTO THESPACE BETWEEN SAID INNER CAP AND SAID OUTFLOW PIPE, SAID OUTFLOW PIPEHAVING THREADS FORMED IN ITS OUTER SURFACE, MEANS MOUNTED ON THE WALLSOF THE CAVITY OF SAID OUTER CAP FOR THREADABLY ENGAGING SAID OUTER CAPWITH THE THREADS ON SAID OUTFLOW PIPE''S OUTER SURFACE, AND A NUTTHREADED ON SAID OUTFLOW PIPE''S OUTER WALLS FOR ENABLING SAID APPARATUSTO BE CLAMPED TO A SUPPORTING SURFACE BETWEEN SAID NUT AND THE END OFSAID OUTER CAP.